Rotating missile emitting light pulses

ABSTRACT

The invention concerns a rotating missile emitting light pulses. The invention is characterized in that means are provided to interrupt said light pulses ( 5 ) when the rotational movement ( 3 ) of the missile ( 2 ) about its longitudinal axis (L-L) stops.

The present invention relates to a rotating missile provided with anemitter of light pulses, addressed to a receiver disposed at a fixedpost (the firing post of said missile) and able to serve in the locationand guiding of said missile, as is for example described in documentU.S. Pat. No. 4,710,028 (FR-2 583 523).

It is known that such an emitter can comprise a voluminous flash lampconsuming significant energy, or else, preferably, a laser source.However, in the latter case, the laser energy emitted must besignificant in order to ensure a long-range optical link resistant topossible jamming. This therefore results in significant ocular risks tothe operators of said missiles, especially in the eventuality that themissile, for example following a motor fault occurring immediately afterthe firing thereof, were to fall to the ground in the vicinity of thefiring post where said receiver and said operators are situated.

The present invention is aimed at remedying this drawback.

To this end, according to the invention, the missile provided with anemitter of light pulses addressed to a receiver disposed at a fixedpost, said missile receding from said receiver while being impressedwith a rotational motion about its longitudinal axis, is noteworthy inthat it comprises means for interrupting said light pulses when saidrotational motion of said missile stops.

Thus, by virtue of the invention, since, when said missile falls to theground, its rotation is no longer possible, there is no longer anyocular risk to the operators of the missile in case of premature andaccidental landing of the latter in the vicinity of the firing post.

Said means for interrupting the light pulses may act in various ways.For example, they may mask said emitter. However, preferably, they haltthe operation of said emitter, either by direct action on it, or byindirect action. In the latter case, when the said emitter is controlledby an electronic control device, said means of interruption may disableeither said device, or the control link between said electronic controldevice and said emitter.

In the case where, in a known manner, said missile comprises a rolldetector emitting roll pulses each of which corresponds to a specificangular position of said missile about its longitudinal axis, it isadvantageous for said roll detector to control said means forinterrupting the light pulses.

Preferably, said means of interruption interrupt said light pulses withdelay with respect to the detection of the first missing roll pulse. Forexample, this interruption occurs after a duration corresponding to atleast two periods of the roll pulses, said duration being meteredstarting from the last roll pulse detected by said detector.

In an advantageous embodiment, said means for interrupting said lightpulses comprise a systematic meter permanently metering at a higherfrequency than the frequency of said roll pulses, said systematic meterbeing reset to zero and reinitialized by each roll pulse that itreceives, whereas, in case of absence of roll pulse, said systematicmeter emits a signal after metering up to a predetermined number,starting from the last roll pulse received.

The figures of the appended drawing will elucidate the manner in whichthe invention may be embodied. In these figures, identical referencesdenote similar elements.

FIG. 1 diagrammatically illustrates the guiding of a rotating missilefrom a fixed firing post.

FIG. 2 diagrammatically shows a roll detector for the missile of FIG. 1.

FIG. 3 is a chart diagrammatically showing, as a function of time t, thesequence of roll pulses generated by the detector of FIG. 2.

FIGS. 4 to 6 are schematic diagrams respectively illustrating threevariant embodiments of the device for interrupting the light pulsesemitted by a missile, in accordance with the present invention.

Represented diagrammatically in FIG. 1 is a firing post 1, able to guidea missile 2 with respect to a reference axis X-X (line of aim). Themissile 2 recedes from the firing post 1 while being impressed with arotational motion about its longitudinal axis L-L. This rotationalmotion has a speed Vr of for example 5 to 10 revolutions per second andis symbolized by the arrow 3. The missile 2 carries a laser emitter 4,for example a VCSEL laser or laser diode emitter 4A (see FIGS. 4 to 6),able to emit laser pulses 5 toward the firing post 1. The lattercomprises a receiver 6 for receiving said laser pulses 5.

As shown diagrammatically in FIG. 2, inside the missile 2 is provided agyroscopic system 7, defining a fixed direction V-V. On this gyroscopicsystem 7 of fixed orientation are fixed a light source 8 and acorresponding receiver 9. Furthermore, around the gyroscopic system 7 isprovided an envelope 10, tied to the missile 2 in its rotation about theaxis L-L. This envelope 10 carries several point-like reflectingsurfaces 11, able to receive the incident light beam 12 emitted by thesource 8 and to address the corresponding reflected beam 13 onto thereceiver 9. The reflecting surfaces 11 are regularly distributed aroundthe envelope 10, for example every 120° (as represented) or every 45°.

Thus, each time a reflecting surface 11 cuts the incident beam 12, thereceiver 9 receives a light pulse, which it transforms into anelectrical roll pulse 14 and, with each revolution of the missile 2about its longitudinal axis L-L, are generated as many electrical rollpulses 14 as the envelope 10 comprises reflecting surfaces 11. Ofcourse, the period T between two successive pulses 14 is equal toT=1/Vrxn, Vr being the speed of rotation of the missile 2 about itself(as mentioned above) and n being the number of reflecting surfaces (seeFIG. 3).

Furthermore, as shown in FIGS. 4 to 6, the receiver 9 is connected to ameter 15, while the laser emitter 4 is controlled by the electronicdevice 16, to which it is connected by a link 17. The meter 15systematically meters at a higher frequency than the frequency 1/T ofthe roll pulses 14 and it is reset to zero and reinitialized by each ofsaid roll pulses 14 that it receives from the receiver 9.

Thus, while the missile 2 is rotating about its axis L-L, the meter 15is permanently reset to zero and reinitialized by the successive rollpulses 14.

On the other hand, if the missile 2 ceases rotating about its axis L-L,for example because it has touched the ground, the roll pulses 14disappear and the meter 15 meters starting from the last roll pulse 14 dreceived—without being reset to zero or reinitialized by any pulse 14—upto a predetermined number corresponding to a duration D greater than thetime T separating the last pulse 14 d received from the first,referenced 14M1, of the missing pulses 14, referenced 14M in FIG. 3. Asis represented in FIG. 3, the duration D is preferably greater than 2T.

When this predetermined number is metered by the systematic meter 15,the latter addresses a control signal to means of actuation 18, by wayof a link 19.

Upon receipt of this latter control signal, said means of actuation 18interrupt the emission of the laser pulses 5 by controlling:

-   -   either a flap 20, which masks the laser diode or the VCSEL laser        4A (FIG. 4);    -   or the halting of the electronic control device 16 through a        link 21 or the halting of the emitter 4 through a link 22 (FIG.        5);    -   or else the opening of an interrupter 23 disposed in the link 17        between the electronic control device 16 and the emitter 4 (FIG.        6).

1-9. (canceled)
 10. A missile provided with an emitter of light pulsesaddressed to a receiver disposed at a fixed post, said missile recedingfrom said receiver while being impressed with a rotational motion aboutits longitudinal axis (L-L), said missile further including a lightinterruption section for interrupting said light pulses when saidrotational motion of said missile stops.
 11. The missile as claimed inclaim 10, wherein said light interrupting section masks the lightpulses.
 12. The missile as claimed in claim 10, wherein said lightinterrupting section halts the operation of said emitter.
 13. Themissile as claimed in claim 12, wherein said emitter is controlled by anelectronic control device, and said light interrupting section halts theoperation of said electronic control device.
 14. The missile as claimedin claim 12, wherein said emitter is controlled by an electronic controldevice, and said light interrupting section disables the control linkbetween said electronic device and said emitter.
 15. The missile asclaimed in claim 10, further comprising a roll detector for said missileemitting roll pulses each of which corresponds to a specific angularposition of said missile about said longitudinal axis (L-L), whereinsaid roll detector controls said light interrupting section.
 16. Themissile as claimed in claim 15, wherein said light interrupting sectioninterrupts the light pulses with delay with respect to the detection ofa first missing roll pulse.
 17. The missile as claimed in claim 16,wherein said light interrupting section interrupts the light pulsesafter a duration (D) corresponding to at least two periods (T) of saidroll pulses, said duration being metered from a last roll pulse detectedby said roll detector.
 18. The missile as claimed claim 15, wherein saidlight interrupting section comprises a systematic meter permanentlymetering at a higher frequency than the frequency of said roll pulses,said systematic meter is reset to zero and reinitialized by each rollpulse that it receives and, in case of absence of a roll pulse, saidsystematic meter emits a signal after metering up to a predeterminednumber, starting from a last roll pulse received.